The present invention generally relates to an actuating device for a mechanical positive actuation of a pressure-response switch, and more particularly, to such an actuating device for guaranting a reliable switch triggering at an exact point during the triggering operation.
An actuating device is disclosed, for example, in German Published, Unexamined Patent Application (DE-OS) 3,406,116, and consists of a so-called switch lug which is loaded mechanically by a control component of a rotary-latch lock. By means of this arrangement, it is possible to actuate an associated pressure switch activating an electromotive drive for a rotary latch of the lock.
In the foregoing actuating device, the switch lug is connected in a conventional way to a housing of a pressure switch, to form a constructional unit. The switch lug is made of a leaf spring equipped with a tracer roller at a free end thereof and is prestressed in the direction of its lift-off advance. The tracer roller of the switch lug thereby bears constantly with a corresponding prestress against the circumference of an associated control cam. Thus, depending on the rotary position of the control cam, the switch lug is maintained in a slightly compressed lift-off position relative to a switch pin of the pressure switch or in a more strongly compressed position bearing on the switch. In the latter position, the switch pin is pressed down into its switch-triggering position as a result of a bending advance of the switch lug.
A problem in the positive actuation of switches such switch lugs as described is above that the switch lugs do not bend identically during every switching actuation. On the contrary, because of other influencing factors, such as the vibrational load exerted on the switch arrangement at the switching time or differing speeds of the control advance exerted on the tracer roller, there is a slight deviation from the intended ideal bending line of the switch lug. Thus, even if the bending of the switch lug is purely elastic, it is impossible to select an exact switch point mechanically.
Furthermore, especially where switches employed under rough conditions of use are concerned, over-elongation of the sensitive switch lugs can occur relatively easily and this can result in extreme deviations of the switch point from the desired value.
Moreover, the principle of switch actuation by means of a switch lug presupposes that there is a control component which can transmit a control advance to the switch lug which is matched to the switching advance of the switch lug.
As a result, the constructive possibilities in the arrangement of the switch or the design of the control component are considerably restricted.
An object of the present invention is, therefore, to improve an actuating device for the mechanical positive actuation of a pressure responsive switch, to the effect that, while greater constructive design freedom is ensured, a reliable switch triggering at an exact point during the switching operation can be guaranteed.
The solution, according to advantageous embodiments of the present invention, for achieving this object and other objects arises from a bend-resistant switch lever being appropriately lengthenable to matching a control advance of a control component which is markedly larger in comparison with a switching advance of a switch pin. As a result, movable levers or the like present in any case can more easily be used additionally as a control component for switch activation.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.